Improvement in liquid-compasses



J. & G. H; uss. Liquid Compass.

No. "L169. Patented Jan. -24. 1871.

N.PETERS. PNDTO-UTHOGRAPHER, WASHINGTON. D. C.

that 7 refine;

JOHN BLISS AND cnonen H. BLISS, or BROOKLYN, NnwYoRK.

' Letters Patent No. 111,169, dated January 24,1871.

IMPROVEMENT IN LIQUID-COM PASSES.

The Schedule referred to in these Letters Patent and making part of thesame.

To all whom it may concern Be it known that we, J OHN' Bnrss and GnonenH. BLISS, of Brooklyn, in the county of Kings and State of New York,have invented a certain new and useful Improvement inLiquid-Gompasses;andv the following is hereby declared to be a correctdescriptionthereof.

Our invention relates First, to employing the metal aluminum with afrosted surface, as the material from which to make the compass-card. Bythe use of this metal for the compass-card, a surface of a pale silverywhite color is obtained, upon which the divisions of the compass can bepainted, and which will show to as good ad vantage as though paintedupon a white surface, thus avoiding the necessity of first painting themetal plate to receive the compass divisions, or the pasting of apaper'card upon said plate, as now usual. The printed card of paper isnot adapted to liquidmompasses, and when a painted ground is used thewhite is liable to be discolored or dissolved by the action ofthe-liquid.

Second, to placing the point of contact of the pivot,

upon which the compass-card turns, with its hearing, at or near thesurface of said compass-card, and the -float above that point; by thusplacing the bearing point of the pivot .upon the same plane asthesurface of the card, the card moves in-.its inclination oroscillation as though upon a horizontalaxis, the center of said axisbeing on the same plane as the surface 'of the card; hence, a point uponthe surface at the cir cumference of said card,'will travel through avery small arc of -circle, because the card will only oscillate upon thepoint, and itsperiphery remain equidistant, or nearly so, from thepivot, instead of swinging laterally, as heretofore usual, where thepoint of motion is either above or below the surface of the card. Inthis construction of the card, the .edge can be allowed to approachnearer to the sides of the bowl on which is placed the ]lll.)l)61"Smark, Without dauger of touching, and the float being above the point.of the pivot, no counterpoise is required on the under side of thecard, as heretofore.

Third, employing glyceriue as the fluid, wholly or partial] ,in which toimmerse the compass-card, magnet, and float. By using this materialalone, or mixed with water or other liquid, a fluid of greater densitythan spirits or spirits and water is' obtained hence, the compass-cardwill not be so easily influenced by the motion of the vessel, and willbe kept in a more horizontal position than heretofore, besides which themagnet or needle of the compass is more easily protected from rust, andcompositions not solu. ble in said mixture are easily obtained forpainting the card, whereas the use of alcohol asthe liquid inv thecompass renders it verydiincult to properly prepare the card and markthe divisions thereon.

In the drawing we have represented a vertical section of the compass andits case, with our improvement applied thereto.

The compass-card a is made of aluminum, with the divisions markeddirectly upon the surface-of the metal, the contrast of the whitefrosted surface of the aluminum and the black or other paint of thedivisions being sulficiently marked to render the card plainly visible,and the surface of the aluminum is not liable to change its color.

The 'compasscard aforesaid may be a complete circle or disk, or it maybe a ring. we have shown the latter.

. The magnet or magnets are to be of proper size and shape; we, however,prefer to use magnets 12, of strips of sheet-steel, as in our patent,the same being attached. to the aluminum-card a by rivets or otherwise.By turning or-foldingro'ver the edgeof the aluminum disk to incloseaudhold the 'endsofi. the strips of steel forming the magnets, they willbe reliably secured in'place.

The float made use of is to be adapted to the weight of the card. \Veprefer to have the pivot d project downward with a float, 0, above thesurface of the card, so that the card will be floated up against itspivot, and the pivot itself will be at or near the level of the surfaceof the card, so that the periphery of the card will always beequidistant from the vertical line of thepivot, even though the card mayoscillate in use.

.The float itself may be made of aluminum, with the edgesof the twodisks folded over and interlocked to render them perfectly air-tight,and to aid in this operation. cementor solder may be used upon theedges. v

I The liquid we introduce into the-compass-case-is glycerine, eitheralone or diluted with alcohol, water,

or other liquid.

The consistency of this glycerine is such that the compass-card becomesquiescent with rapidity, and the divisions of the card are not liable tobecome ob-' literate'd nor the needle rusted orinjured.

A mixture of glyceriue, in proper proportions, is

not liable to freeze, even at very low temperatures.

Glycercine and its mixtures undergo a much smaller amount of expansionunder increase of temperature than alcoholic mixtures; thereis,'therefore, very little strain on the compass-bowl due to increase ofteinperature.-

We claim as our inventiou i 1. A compass-card of aluminum, with afrosted surface, and divisions painted upon that surface, substantiallyas set forth.

-verted pivot, when the pivot projects below the up- 'for the purposesspecified; W

2. The float and compass-cord, both constructed of, aluminum, andcombined together substantially as specified.

3. A liquid-compass, in which the liquid that float-s the card isglycerine, or its mixtures, for the purposes specified.

4. A'compass-card and float combined, with an in- Witnesses:

HAROLD SERRELL, l V "Geowlhuoimmr. V

per portion of the flout or floats,- substaiutially as and

